It has become increasingly popular in recent years to use supplemental heating devices in buildings. For example, wood-burning stoves, fireplaces, propane heaters and kerosene heaters are often used to provide heating in many homes or places of businesses. Typically, these supplemental heating devices are not part of the building's central heating system and they are usually located in only one room of the building. This gives rise to a substantial drawback which is often associated with tehse supplemental heating systems. Namely, the warm air generated by these systems is poorly distributed throughout the building. In fact, the warmed air can be confined to a very small area, often only one room of the building. Thus, some rooms are left uncomfortably cold, while others are unpleasantly over-heated. This poor utilization of the heat generated by supplemental heating units makes supplementary heating devices less attractive and uneconomical.
This poor utilization is due, in large part, to the inability of the warmed air to redistribute itself throughout the building. Natural convection currents are ill-suited to move warm air first, laterally through a building, and then upwards to higher floors through available pathways, such as stairwells. Further, there is seldom any provision made for mechanical redistribution of the air which is warmed by the supplemental heating device and the ductwork, if any, of the central heating system is poorly adapted to collect and redistribute heat which is generated anywhere other than the central furnace.
The problem of poor distribution of heated air within a building also occurs in situations other than those involving supplemental heating devices. For example, a building with a poorly balanced central heating system or a building to which an addition has been made may face this problem.
Any permanent system or device for the redistribution of warmed air through a building should be functional during cold weather and yet be capable of being disabled during warmer weather when its operation would be unnecessary or even undesirable. This should be accomplished by as rapid and simple a means as possible.
Finally, any such device must have a pleasing appearance and be unobtrusive. These considerations are especially important in homes.